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Prevent stack overflow when evaluating input arguments

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This commit is contained in:
Sipke Schoorstra 2023-03-02 21:19:23 +01:00
parent 67efc51ebb
commit b02755a378
3 changed files with 84 additions and 27 deletions
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13
src/modules/Elsa.JavaScript/Features/JavaScriptFeature.cs
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@ -33,6 +33,13 @@ public class JavaScriptFeature : FeatureBase
/// <inheritdoc />
public override void Configure()
{
Module.UseWorkflowManagement(management => management.AddActivitiesFrom<JavaScriptFeature>());
}
/// <inheritdoc />
public override void Apply()
{
// JavaScript services.
Services
.AddSingleton<IExpressionSyntaxProvider, JavaScriptExpressionSyntaxProvider>()
.AddSingleton<IJavaScriptEvaluator, JintJavaScriptEvaluator>()
@ -41,6 +48,7 @@ public class JavaScriptFeature : FeatureBase
.AddExpressionHandler<JavaScriptExpressionHandler, JavaScriptExpression>()
;
// Type definition services.
Services
.AddSingleton<ITypeDefinitionService, TypeDefinitionService>()
.AddSingleton<ITypeDescriber, TypeDescriber>()
@ -50,7 +58,8 @@ public class JavaScriptFeature : FeatureBase
.AddSingleton<ITypeDefinitionProvider, CommonTypeDefinitionProvider>()
.AddSingleton<ITypeDefinitionProvider, VariableTypeDefinitionProvider>()
;
Module.UseWorkflowManagement(management => management.AddActivitiesFrom<JavaScriptFeature>());
// Handlers.
Services.AddNotificationHandlersFrom<JavaScriptFeature>();
}
}

73
src/modules/Elsa.JavaScript/Handlers/WorkflowDefinitionActivityJavaScriptHandler.cs Normal file
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@ -0,0 +1,73 @@
using Elsa.Expressions.Models;
using Elsa.Expressions.Services;
using Elsa.Extensions;
using Elsa.JavaScript.Notifications;
using Elsa.Mediator.Services;
using Elsa.Workflows.Core.Models;
using Elsa.Workflows.Management.Activities;
using Elsa.Workflows.Management.Extensions;
using Elsa.Workflows.Management.Services;
using Humanizer;
using JetBrains.Annotations;
using Jint;
namespace Elsa.JavaScript.Handlers;
/// <summary>
/// Configures the JavaScript engine with workflow input getters.
/// </summary>
[PublicAPI]
public class WorkflowDefinitionActivityJavaScriptHandler : INotificationHandler<EvaluatingJavaScript>
{
private readonly IActivityRegistry _activityRegistry;
private readonly IExpressionEvaluator _expressionEvaluator;
/// <summary>
/// Constructor.
/// </summary>
public WorkflowDefinitionActivityJavaScriptHandler(IActivityRegistry activityRegistry, IExpressionEvaluator expressionEvaluator)
{
_activityRegistry = activityRegistry;
_expressionEvaluator = expressionEvaluator;
}
/// <inheritdoc />
public async Task HandleAsync(EvaluatingJavaScript notification, CancellationToken cancellationToken)
{
var engine = notification.Engine;
var context = notification.Context;
// If we are already evaluating inputs, then we're in a circular evaluation loop. In this case, we should not attempt to evaluate the inputs.
if(context.TransientProperties.TryGetValue("EvaluatingInputs", out var evaluatingInputs) && (bool)evaluatingInputs)
return;
// To prevent a circular evaluation loop, set a flag on the context to indicate that we're currently evaluating the inputs.
context.TransientProperties["EvaluatingInputs"] = true;
// Create input getters.
await CreateInputAccessorsAsync(engine, context);
}
private async Task CreateInputAccessorsAsync(Engine engine, ExpressionExecutionContext context)
{
var workflowDefinitionActivity = GetFirstWorkflowDefinitionActivity(context);
if (workflowDefinitionActivity == null)
return;
var descriptor = _activityRegistry.Find(workflowDefinitionActivity.Type, workflowDefinitionActivity.Version)!;
var inputDefinitions = descriptor.Inputs;
foreach (var inputDefinition in inputDefinitions)
{
var inputPascalName = inputDefinition.Name.Pascalize();
var input = workflowDefinitionActivity.SyntheticProperties.TryGetValue(inputDefinition.Name, out var inputValue) ? (Input?)inputValue : default;
var evaluatedExpression = input != null ? await _expressionEvaluator.EvaluateAsync(input, context) : input;
engine.SetValue($"get{inputPascalName}", (Func<object?>)(() => evaluatedExpression));
}
}
private static WorkflowDefinitionActivity? GetFirstWorkflowDefinitionActivity(ExpressionExecutionContext context) =>
context.GetActivityExecutionContext().GetFirstWorkflowDefinitionActivity();
}

25
src/modules/Elsa.JavaScript/Services/JintJavaScriptEvaluator.cs
View file

@ -74,8 +74,6 @@ public class JintJavaScriptEvaluator : IJavaScriptEvaluator
// Create variable & input setters and getters for each variable.
CreateMemoryBlockAccessors(engine, context);
// Create input getters.
await CreateInputAccessorsAsync(engine, context);
engine.SetValue("isNullOrWhiteSpace", (Func<string, bool>)(value => string.IsNullOrWhiteSpace(value)));
engine.SetValue("isNullOrEmpty", (Func<string, bool>)(value => string.IsNullOrEmpty(value)));
@ -93,29 +91,6 @@ public class JintJavaScriptEvaluator : IJavaScriptEvaluator
return engine;
}
private async Task CreateInputAccessorsAsync(Engine engine, ExpressionExecutionContext context)
{
var workflowDefinitionActivity = GetFirstWorkflowDefinitionActivity(context);
if (workflowDefinitionActivity == null)
return;
var descriptor = _activityRegistry.Find(workflowDefinitionActivity.Type, workflowDefinitionActivity.Version)!;
var inputDefinitions = descriptor.Inputs;
foreach (var inputDefinition in inputDefinitions)
{
var inputPascalName = inputDefinition.Name.Pascalize();
var input = workflowDefinitionActivity.SyntheticProperties.TryGetValue(inputDefinition.Name, out var inputValue) ? (Input?)inputValue : default;
var evaluatedExpression = input != null ? await _expressionEvaluator.EvaluateAsync(input, context) : input;
engine.SetValue($"get{inputPascalName}", (Func<object?>)(() => evaluatedExpression));
}
}
private static WorkflowDefinitionActivity? GetFirstWorkflowDefinitionActivity(ExpressionExecutionContext context) =>
context.GetActivityExecutionContext().GetFirstWorkflowDefinitionActivity();
private static void CreateMemoryBlockAccessors(Engine engine, ExpressionExecutionContext context)
{